Sound reproducing stylus



July 27, 1943. R s M 2,325,343

SOUND REPRODUC ING STYLUS Filed Jan. 28, 1942 gwvwwtoo ROBERT E. SEMPLE Patented July 27, 1943 SOUND REPRODUCING STYLUS Robert E. Semple, Youngstown, Ohio, assignor to The Astatic Corporation, Youngstown, Ohio, a

corporation of Ohio Application January 28, 1942, Serial No. 428,511

13 Claims.

This invention relates to sound reproduction apparatus and more particularly to a reproducing stylus for engaging a sound record and transmitting the mechanical vibrations to an element of the reproducing mechanism such as, a mechanical-electrical transducer, for example. For reasons to be hereinafter fully explained the stylus of the invention is particularly well suited for use in connection with a piezo-electric translating element although it should be understood that the stylus is capable of general application and retains its principal advantages regardless of the type of translating element with which it is used.

A principal source of difficulty in the normal operation of conventional photograph reproducing apparatus is the ease with which the record engaging stylus point may become damaged by allowing the pick-up arm carrying the stylus to fall onto the record or by moving the stylus laterally against the periphery of the record tablet. Also such occurrences damage the record and in cases of severe shock the translating mechanism to which the stylus is attached may also be damaged.

The primary object of the invention is the provision of an improved stylus which may be substituted in any transducer or translating assembly for the conventional styli now employed but which is operative to protect the stylus and the record from injury if the arm and stylus is allowed to drop onto the record or if the arm is swung about to bring the stylus into collision with the periphery of the record.

A further object of the invention is the provision of an improved phonograph reproducing stylus which is operative to reduce the objectionable noise level and which effects better tracking of the record groove whereby the fidelity of the reproduction is enhanced. This result is achieved by mounting the record groove engaging element of the stylus on a carrier which is yieldable in a vertical plane so that the element will readily override any foreign particles lodged in the record grooves without transmitting the movement to the principal mass of the stylus and pick-up arm.

The use of the stylus of the invention enables the mechanical-electrical transducer assembly, particularly if the same is of a piezo-electric type, to be made more economically and more ruggedly since the transducing element and its immediate coupling devices may be made considerably stiffer, the mechanical motion loss normally required to be built into such assemblies being absorbed by a yieldable element employed in the stylus of the invention.

These and other objects and advantages of the invention will become apparent from aconsideration of the following detailed specification and the accompanying drawing wherein there is specifically disclosed a preferred embodiment of the invention.

In the drawing:

Figure 1 is a side elevation of a phonograph reproducing stylus constructed in accordance with the invention; and

Figures 2 and 3 are a front elevation and a top 1plan, respectively, of the apparatus of Figure Referring to the illustrated embodiment of the invention, reference numeral Ill designates an elongated body member having a shank substantially equal in diameter to the shank of the conventional needle-like stylus. The shank of body member I0 is provided with a flattened portion II against which the screw of the stylu retaining assembly of the transducer is adapted to lodge to retain the body member ID in fixed angular relation to the transducer and the arm carrying the same. The lower end of the member ID is flattened and bent outwardly to provide a foot or guard l2 which extends outwardly of the body member on the same side thereof as the flattened portion II. The foot or guard I2 is rounded at its lower extremity, as indicated in Figure 1, and is .of such lateral dimension that it forms a guard for the record groove engaging element which is positioned immediately in front of it and will not damage the record if it is forced down into engagement with the top surface of the record. The body 10 is formed of cold rolled steel or other tough steel or material so that it will stand severe shocks and forces without becoming deformed.

While obviously the angle between the principal axis of the body 10 and the vertical will depend on the construction of the stylus holder, it is found, in practice, that this angle is normally 21.5. By making the angle between said principal axis and the longitudinal axis of the foot l2 approximately 43 satisfactory results have been achieved in the operation of the stylus although it should be understood that this angle may be varied.

An annular groove I3 is formed in the body 10 above the base of the foot 12 and soldered or otherwise rigidly secured in this groove is an integral loop l4 of a length of piano wire I5. Wire l5 extends generally parallel above the middle of the foot l2 and is bent upwardly at a. point which is past the end of the foot to provide a generally horizontal end portion It.

In accordance with the preferred and illustrated embodiment of the invention the stylus tip is made from a gem or a semi-precious stone such as a sapphire, for example, and this tip is indicated by reference numeral [1 in the drawing. In accordance with common practice the jewel I1 is embedded in and held by a turning it which is preferably constructed of brass. The upper end of turning I8 is slotted diametrically and the horizontal portion it of the wire it is rigidly secured therein by soldering of otherwise. To insure a tight flt the portionifi of the wire it is flattened, vertically, as indicated in Figures 2 and 3. y

In operation, the mechanical vibrations generated by the undulations in the moving record groove are picked up by the tip Ill and are transmitted to the body In through the music wire it. Wire l5 possesses sufficient rigidity to transmit the vibrations without appreciable loss in amplitude but is yieldable to permit flexing thereof and the foot l2 to engage the record when more than approximately four ounces of pressure is applied to the shank Hi. This operation prevents damage to the stylus point and to the record in the event the stylus is dropped onto the record or is lowered onto the record at too high a rate of speed. The characteristic of the wire i5 is such that the parts assume their normal relative positions when the excess pressure is removed.

The guard l2 also protects the stylus point against damage by lateral collision as when the stylus is bumped against the periphery of the record.

It should now be apparent that I have provided a sound reproducing stylus which accomplishes the objects initially set out. The assembly protects the stylus point or tip and the record as explained above and it should be apparent that by reason of the yieldable nature of the driving wire 85, any abrupt change in the depth of the record groove will be readily absorbed and not transmitted to the transducer and arm.

The above specifically described embodiment or the invention should be considered as illustrative only as obviously many changes may be made therein without departing from the spirit or scope of the invention. For example, suitable dampening material may be inserted between the wire l5 and the foot 82 if it is found that the wire has a natural frequency within the range of the vibrations picked up by the stylus point. Also it is contemplated that various types of stylus points or tips may be employed in the combination including the expedient of constructing the end of the wire 95 of suitable material and pointing this end to form the groove engaging tip. Moreover, any linkage which accomplishes the function of the wire l5 may obviously be employed in place of the wire. Reference should therefore be had to the appended claims in determining the scope of the invention.

What I claim is:

1. A record engaging stylus for a phonograph reproducing mechanism comprising in combination a rigid shank adapted to be secured to the mechanism, a flexible member rigidly secured to said shank, a. pointed record groove engaging element carried by said flexible member, and foot on the lower end of said shank adapted to enga e the record upon flexing of said flexible member.

2. A record engaging stylus for a phonograph reproducing mechanism comprising in combination a relatively stifl rod having an angularly disposed guard at its lower end, a flexible member secured to said guard, and a pointed record groove engaging element carried by said flexible member outwardly of said guard, the arrangement being such that upon upward flexing of said flexible member the guard will engage the upper surface of the record.

3. A record engaging stylus for a phonograph reproducing mechanism comprising in combination a relatively stiiI rod having an angularly disposed guard at its lower end, a flexible member secured to said rod and overlying said guard, and a pointed record groove engaging element carried by the outer end of said flexible member, the arrangement being such that upon upward flexing of said flexible member the guard will engage the upper surface of the record.

4. A phonograph reproducing stylus comprising a body member having a shank adapted to be received in a transducer socket, the lower end of said member being provided with an outwardly extending foot, a flexible member extending outwardly of said body member and rigidly secured to said body member above said foot, and a pointed record groove engaging element carried by the outer end of said flexible member.

5. A phonograph reproducing stylus comprising a body member having a shank adapted to be received in a transducer socket, the lower end of said member being provided with an outwardly extending foot, a recess in said member above said foot, a yieldable member partially received in said recess and extending outwardly of said foot, and a pointed record groove engaging element carried by the outer end of said yieldable member.

6. A phonograph reproducing stylus comprising a body member having a shank adapted to be received in a transducer socket, the lower end of said member being provided with an outwardly extending foot, a circumferentially extending groove in said member above said foot, an elongated yieldable member extending outwardly beyond said foot and having a portion of its length received in said goove, and a pointed record groove engaging element carried by the outer end of said yieldable member.

'7. Apparatus according to claim 6 further characterized in that said yieldable member overlies said foot.

8. Apparatus according to claim 6 iurthe including a holder for said element, said holder being provided with a recess adapted to receive a portion of said yieldable member.

9. A phonograph reproducing stylus comprising a shank to be received in a transducer socket, the lower portion of said shank being flattened and bent angularly outward to provide an integral guard, a yieldable vibration transmitting member overlying said foot and rigidly attached at one end to said shank, and a pointed record groove engaging element rigidly carried by the other end of said transmitting member.

10. Apparatus according to claim 9 further characterized in that said shank is provided with a flattened surface on the side thereof from which said foot extends.

11. Apparatus according to claim 9 further characterized in that said shank is provided with a flattened surface on the side thereof from which said foot extends, said transmitting member being flxedly connected with said shank and element whereby the alignment of said surface, transmitting member and element is maintained.

12. A phonograph reproducing stylus comprising a relatively stifl shank adapted to be received in a transducer socket, a laterally extending foot 5 on the lower end of said shank, a yieldable vibration transmitting member rigidly connected to said shank and positioned above said foot, 9. pointed record groove engaging element, a

mounting for said element, and means rigidly 10 Disclaimer 2,325,343.R0bert E. Sample, Youngstown, Ohio. SOUND REPRODUCING STYLUS. Patent dated July 27, 1943. Disclaimer filed June 5, 1950, by the assignee, The Astat'ic Corporation. Hereby enters this disclaimer to claims 1, 2, 4, and 13 of said patent.

[Ofiicial Gazette July 11, 1950.] 

